TUNNELING THROUGH RECTANGULAR QUANTUM DOTS AT HIGH MAGNETIC-FIELDS

Transport in a quasi-one-dimensional wire containing a rectangular quantum dot in a strong magnetic field is studied numerically. As the width of the wire is varied, a rectangular dot on the wire introduces peak or dip structures in the conductance. The charge-density distribution and current-flow pattern clearly show that the Landau-level coupling between the sere-dimensional (OD) state and the extended state is the origin of these structures. At the resonant points, which correspond to OD states in the dot, Landau-level coupling becomes essential and the propagation of one Landau level is enhanced or blocked by the OD state of a different Landau level.